Railway traffic controlling apparatus



July 24, 1962 H. w. BRYAN RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 27, 1959 n Y mmwk @NSN @miv SSS @wm R. a E m Nw @S NNN gb@ Snug *Il w o au N ANS NN W x@ mN MW Umlm mm mw ww n A imm Ha H #ALL .AW n w Nw Q R fe A 'E A G w mw im@ l wbnm. R miti U MSNS@ mwwmww n n n www NN, Sv mwvgwvmv NNW ,WNNQNNN lllllll ||L IIII .IIL llllll NNNNNQ mmwmwwm .Q SRAS 2S @www @www swwvw @gmx QN NSPQBQ wmwww Q @$59991 WN \IV.. YS u v5 A A AEA United States Patent @i 3,046,391 RAILWAY TRAFFIC CONTROLLING APPARATUS Harold W. Bryan, Penn Hills, Pa., assgnor to Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania Filed May 27, 1959, Ser. No. 816,253 8 Claims. (Cl. 246-63) My invention relates to railway traflic controlling rapparatus, and particularly to train carried automatic train control apparatus employing acknowledging means.

In continuous inductive train control systems, :acknowledging means are generally provided whereby the engineman is required to acknowledge a change in the cab signal indication when the change is to a more restrictive indication. The `failure of the engineman to acknowledge such la change results in an automatic brake application, but if the change to the more restrictive indication is acknowledged within a predetermined time the automatic brake application is forestalled.

It has been found that under some conditions it may be expedient for safer operation of trains to prevent the acknowledgement of =a change in a cab signal from a clear directly to a slow speed or stop indication, such change possibly denoting a suddenly occurring ldangerous condition in the signal block occupied by the train. It has also been found that it may be expedient in some instances to arrange the wayside control apparatus supplying the cab signal control energy to the track rails to supply clear control cab signal energy to a short section of track immediately in the rear of a point at which a stop is desired, thereby temporarily changing the cab signal indication to clear and then directly to stop when the train passes the desired stop point. By providing such an arrangement and by preventing an acknowledgement of the change from the clear to the stop indication by means of the apparatus embodying my invention, an absolu-te stop is enforced which, as for example when a train is approaching an open drawbridge, may prevent a serious accident.

It is `accordingly the object of my invention to pro-vide apparatus incorporating a novel arrangement of acknowledging circuits whereby acknowledgement of a cab signal change from a `clear indication directly to a slow speed or stop indication is prevented and, therefore, an automatic brake application following such change cannot be forestalled.

It is another object of my invention to provide reset means for resetting the apparatus after such a cab signal change and automatic brake application,

Other features, objects, and advantages of my invention will appear as the specication progresses.

'I shall describe one form of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

The accompanying drawing is a diagrammatic view showing one form of apparatus embodying my invention.

Referring to the drawing there is shown a stretch of railway track including a track section designated T compri-sing rails designated 1 and 2, and extending between lirst and second points of locations designated by the reference characters A and B, respectively. The rails of the section of railway track are separated at locations A and B from the rails of the remainder of the track stretch by insulated joints designated J, thereby forming what is commonly known in the art as a railway signaling block. A locomotive or engine designated by the reference character L is shown adjacent point A -by a geometric figure drawn by broken lines, and it is to be understood that trains traversing the section of railway track do so in la direction from west to east, or left to right, as shown in the drawing by the pointed or arrow- Patented July 24, 1962 head portion of said geometric ligure representing the engine or locomotive.

There is also shown adjacent points A and B, in block diagram form, the engine carried cab signaling current responsive apparatus, and the cab signaling current coding apparatus, respectively. The block diagram adjacent point B is shown as connected lto the rails 1 and 2 of track section 2 and is noted on the drawing as applying cab signaling current to the rails in accordance with traic conditions in advance, which, in accordance with the aforesaid direction of traic through the track stretch, would be to the right yof point B. The apparatus represented by the block diagrams forms no part -of my present invention but is shown for purposes of making -this description complete.

Three control relays R1, R2, and R3, which are commonly known in the art as the slow speed train control relay, the caution train control relay, and the clear or proceed train control relay, respectively, also appear in the drawing. 'The detailed `control arrangement for these relays is not show-n but isrepresented by the dotted lines extending from the Iblock diagram representing the engine carried cab signaling current responsive apparatus. The ycontrol relays, the detailed control arrangement therefor, and the apparatus represented by the block diagrams may, `for example, be controlled in the manner described for similar :apparatus shown in Letters Patent of the United States, No. 1,986,679, issued January l, 1935, to Lloyd V. Lewis for Railway Tralic `Controlling Apparatus. It is sufcient for `an understanding of my present invention to state that relays R1 and R3 are energized under clear or proceed trac conditions, relays R1 and R2 are energized under approach medium conditions, relay R1 alone is energized under caution or approach conditions, and all three of the relays are deenergized 4under slow speed or stop conditions. The correspondence between ythe cab signaling current lapparatus and relays R1, R2, and R3 shown in the drawing of this application, andthe similar apparatus of the Lewis patent will be readily Iapparent from an examination of the patent.

Three acknowledging stick relays, designated by the reference characters S1, S2 and S3, and of the neutral type, are also shown in the drawing. Relays S2 and S3 are each shown as having an upper or pickup winding, and ya lower or stick winding, such relays being of a construction well known in the art. The reference character ASW designates a manually operable acknowledging switch, shown in the conventional manner, and having a normally closed or normal contact a closed in the normal position of the switch and a normally open or reverse Contact b closed in the reverse position of the switch. Reference character RSW designates a second or reset switch similar to the acknowledging switch and also having a normally closed or normal Contact a closed in the normal position of t-he switch and a normally open or reverse contact b closed in the reverse position of the switch. When'either of the switches is operated its normally closed contact a becomes opened and its normally open contact b becomes closed.

Reference character MV designates the winding of a brake valve controlling magnet which is normally energized, but which when deenergized serves to cause an automatic application of the brakes of the train equipped with the apparatus of my invention. This winding corresponds to the winding l5S of the valve designated by the reference character'G in the aforesaid Lewis patent. The method by which the magnet valve controls a brake application forms no part of my invention and reference is made nto the Lewis patent for an understanding of the operation of the braking apparatus controlled by the magnet valve. However, it should be pointed out that the deenergization of the winding of the magnet valve does not immediately cause an application of the brakes of a train but, as noted on the drawing, a delay period is introduced such, for example, as a period of time of 6 seconds, before a brake application results after the deenergization of the winding. This delay period normally allows time for the engineman to acknowledge a change in cab signal indication Ito a more restrictive indication and thereby forestall the brake application, as will become more apparent as the description progresses.

There is also shown on the left hand side of the drawing the cab signal lamps which are selectively illuminated to indicate to the engineman the traffic conditions in advance of the train. These lamps are designated GE, YGE, YE, and RE for green, yellow over green, yellow, and red aspects, respectively, or the clear, approach medium, approach, and stop indications, respectively. The control circuits for the illumination of the lamps will be described hereinafter in this description,

It should be pointed out at this time that a suitable source of control current is provided, this current source being preferably a battery of proper voltage and capacity, but for the sake of simplicity this power source is not shown in the drawing, its positive and negative terminals being identitied by the conventional reference characters B and N, respectively.

It should be further pointed out that all contacts of the relays are not located on the drawing directly below the symbol representing the winding -of their respective relay, but each contact that is not so located is designated by the reference character for its respective relay disposed on the drawing directly above the movable portion of the contact, as is believed will be readily apparent from an examination of the drawing.

It is believed that the operation of the apparatus of my invention can best be understood by describing the operation under specific instances of changes in the cab signal indications.

It will first be assumed that the train equipped with the cab signal apparatus is traveling under clear traflic conditions and, therefore, relays R1 and R3 are energized, and relays R2, S1, S2 and S3 are all deenergized, this condition of the apparatus being considered to be the normal condition. The green cab signal lamp GE is illuminated under these conditions, being energized by a circuit extending from terminal B of the battery over the front point of contact a of relay R3 to the lamp filament, `and through the filament to terminal N of fthe battery. An energizing circuit for the winding MV of the valve is also closed at this time, this circuit extending from terminal B of the battery over the front point of contact a of relay R3, the back point of contact c of relay S3, the back point of contact b of relay S2, normally closed Contact a of acknowledging switch ASW, and through the winding MV of the magnet valve to terminal N of the battery.

I will now assume that the trafc conditions in the stretch of railway track traveled by the train change to approach medium conditions so that relay R3 becomes deenergized and relay R2 becomes energized. The previously traced energizing circuits for winding MV and' the green signal lamp will at this time be opened at the open front point of contact a of relay R3. The green signal lamp will be extinguished and the magnet valve will operate =to initiate a brake application unless another circuit for the magnet valve is closed within the previously mentioned 6 second delay period. The release of relay R3 and energization of relay R2 closes an energizing circuit for illuminating lamp YGE to give an approach medium indication. This circuit may be traced `from terminal B of the battery over 'the back point of contact a of relay R3, the front point of contact a of relay R2, and through the lament of the lamp YGE, to terminal N of the battery. If the engineman alt this time acknowledges the change in indication by momentarily operating the acknowledging switch ASW to its reverse position and then returning it to its normal position within the 6 second delay period, winding MV will be reenergized and a brake application will be averted. This operation is accomplished in the following manner. The movement of switch ASW to its reverse position closes a circuit for the energization of relay S3. This circuit extends from terminal B of the battery over the back point of contact a of relay R3, normal contact a of switch RSW, reverse contact b of switch ASW, the front point of contact c of relay R1, and through the pickup winding of relay S3 to terminal N of the battery. Relay S3 is thus picked up and completes its stick circuit over its own front contact a to the lower or stick winding of the relay. This stick circuit is obvious and no detail description thereof is considered necessary. When the engineman returns the acknowleging switch to its normal position, an energizing circuit is cornpleted for the winding MV of the magnet valve which may be traced from terminal B of the battery over the back point of contact a of relay R3, the front point of contact a of relay R2, the front point of contact c of relay S3, the back point of contact b of relay S2, contact a of switch ASW closed in its normal position, and through the winding MV of the magnet valve to terminal N of the battery. Relay S3 is retained energized over its stick circuit as long as relay R3 remains deenergized, and the winding MV is therefore retained energized over the front point of contact c of relay S3 so long as relay R3 remains released.

It will now be assumed that the traic conditions under which the train is traveling change again to clear and relay R3 is again energized and relay R2 is deenergized. The energization of relay R3 opens at the back point of its Contact a the stick circuit for relay S3 which releases and closes over the back point of its contact c the previously described energization circuit for winding MV including the front point of contact a of relay R3. No acknowledgement of the change from an approach medium indication to a clear indication is, therefore, required. Signal lamp YGE is extinguished and the circuit for the energization of signal lamp GE is again closed to illuminate that lamp and again give the clear indication.

Assuming now that, after the previously described change to the approach medium indication and acknowledgement thereof. the traic conditions further change to approach conditions, relay R2 will be released and relay R1 will remain energized. The release of relay R2 opens at the front point of its contact a the previously described energizing circuit for lamp YGE which is thus extlnguished, and closes at the back point of its contacts a an energizing circuit for lamp YE. This circuit extends from terminal B of the battery over the back point of contact a of relay R3, the back point of contact a of relay R2, the back point of contact b of relay Sl, the front point of contact a of relay R1, and through the filament of lamp YE to terminal N of the battery. Lamp YE is thus illuminated to give the approach cab signal indication. The release of relay R2 also opens at the front point of its contact a the energizing circuit for winding MV which will enforce an automatic brake application 1f the cab signal change is not acknowledged. lt will be assumed, however, that the engineman acknowledges the change, within the period of time allowed, by moving the acknowledging switch to its reverse and then again to its normal position. The movement of switch ASW to its reverse position closes at contact b of the switch pickup circuits for relays S2 and S3. The pickup and stick circuits for relay S3 are the same as previously described. The circuit for picking up relay S2 extends from terminal B of the battery over the back point of contact a of relay R3, contact a of switch RSW closed in its normal position, contact b of switch ASW closed in its reverse position, the pickup winding of relay S2, and over the back point of contact b of relay R2 to terminal N of the battery. Relay S2 is thus energized closing its stick circuit to its stick winding including its own front contact a and the back points of contacts a of relays R2 and R6. When the engineman returns the switch to its normal position an energizing circuit for magnet valve Winding MV is closed which extends from terminal B of the battery over the back point of contact a of relay R3,-the back point of contact a of relay R2, the back point of contact b of relay S1, the front point of contact a of relay R1, the yback point of contact c of relay S1, the front point of contact b of relay S2, contact a of switch ASW closed in its normal position, and through the winding MV of the magnet valve, to terminal N of the battery, Magnet valve winding MV is thus reenergized and an automatic brake application suppressed.

Upon a change in the cab signal from approach to approach medium the stick circuit for relay S2 is opened at the back points of contacts a and b of relay R2, and relay S2 releases to recomplete the previously described energizing circuit for magnet valve winding MV including the back point of contact b of relay S2 and the front point of contact c of relay S3. Similarly, upon a change in the cab signal from approach directly to clear, the stick circuits for relays S2 and S3 are opened at the back point of contact a of relay R3 and relays S2 and S3 release to recomplete the previously described energizing circuit for magnet winding MV including the back points of contacts b and c of relays S2 and S3, respectively. Thus an acknowledgement of a cab signal change from approach to approach medium, or directly to clear is not required.

I will now assume that the previously described change from an approach medium indication to an approach indication was acknowledged and, therefore, relays R1, S2 and S3 are picked up and relays R2 and R3 are released. I will further assume that at this time the traflic conditions so change as to cause a change in the cab signal indi. cation from appro-ach to slow speed or stop. Under these conditions relay R1 will now release, and an energizing circuit for the filament of lamp RE will be closed which may be traced from terminal B of the battery over the back point of contact a of relay R3, the back point of contact a of relay R2, the back point of contact b of relay S1, the [back point of contact a of relay R1, and through the lament of lamp RE to terminal N of the battery. The cab signal now displays a red aspect and gives a stop or slow speed indication. The release of relay R1 also opened a-t the front point of its contact a the previously described energizing circuit for magnet valve winding MV thus requiring an acknowledgement to prevent a brake application. The engineman, therefore, again reverses the acknowledging switch ASW and then returns it to its normal position. The reversal of the switch closes a pickup circuit for relay S1 which extends from terminal B of the battery over the back point of contact a of relay R3, normal contact a of switch RSW, reverse contact b of switch ASW, the back point of contact c of relay R1, front contact b of relay S3, the winding of relay S1, and over the back point of contact b of relay R1 and over the back point of contact b of relay RZ to terminal N of the battery. Relay S1 is thus picked up completing its stick circuit including its own front contact a. FIlhis circuit extends from terminal B of the battery over the back points of contacts a of relays R3 and R2, the front point of Contact b of relay S1, the front point of contact a of relay S1, the winding of relay S1, and over the back point of contact b of relay R1 and the back point of contact b of relay R2 to terminal N of the battery. Relay S1 is thus retained picked up at this time. The energizing circuit for the lilament of lamp RE is now completed over front point of contact b of relay S1. When switch ASW is returned to its normal position, magnet valve winding MV is energized by a circuit extending from terminal B of the battery over the front point of contact c of relay S1, the front point of contact b of relay S2, norm-al contact a of switch ASW,

E and through the winding MV to terminal N of the battery. An automatic brake application is thus suppressed.

Upon a change in a cab signal indication directly from the approach medium indication to the stop or slow speed indication the red lamp is illuminated by the previously described energizing circuit for that lamp. However, under these conditions relay S2 is not `energized as no acknowledgement of the change in indication from approach medium to approach has been previously required. When switch ASW is moved to its reverse position, however, both relays S1 and S2 are energized along with relay S3 which was previously energized, the three relays cornplete their stick circuits, and the apparatus then stands `as if an acknowledgement of a change from an approach medium to an approach indication had been made. Upon the return of the switch ASW to its normal position the circuits operate to energize winding MV in the identical manner described for the energization of that winding upon the acknowledgement of a change in indication from approach to stop. The circuits also operate in a similar manner upon a change in cab signal indication directly from clear to approach. That is, relay S3 is not energized under these conditions because no acknowledgement in a change `from a clear to an approach medium indication has been previously required. However, when switch ASW is reversed to acknowledge the change from clear to approach, the pickup windings of both relays S2 and S3 are energized over their previously described pickup circuits and the apparatus then stands as if acknowledgement of a change from clear to approach medium had previously bee-n made and a change from approach medium to approach has just been initiated. The pickup of relays S2 and S3 completes their stick circuits and the relays are maintained energized. When the engineman now lreturns switch ASW to its normal position magnet valve winding MV will again be energized and a brake application suppressed.

A change in cab signal indication from stop to approach, approach medium, or clear does not require an acknowledgement because the stick circuit for acknowledging relay S1 is opened upon the pickup of relay R1, the stick circuits for acknowledging relays S1 and S2 are opened upon the energization of relay R2, and the stick circuits for relays S1, S2 Iand S3 are opened upon the I energization of relay R3. Magnet valve winding MV is therefore momentarily deenergized and immediately reenergized over one of its previously described energizing circuits when a change in cab signal indication from stop to a less restrictive indication occurs.

I will now describe the operation of the apparatus of my invention when a change in the cab signal from a clear indication directly to a stop or slow speed indication occurs, and the manner in which the acknowledgement of such a change and thereby suppressing an automatic brake application, is prevented.

As previously pointed out relays Rl and R3 are energized and relays R2, S1, S2, and S3 are all deenergized when the cab signal is displaying a green aspect giving a clear indication. 'When 4the cab signal changes directly to display a red aspect and thus gives a stop or slow speed indication, relays R1 and and R3 become deenergized and the previously described energizing circuit for the illumination of lamp GE is opened and the energizing circuit or the illumination of lamp RE is closed. The circuit for the energization of magnet valve winding MV is also opened at this time at the front point of contact a of relay R3. When the engineman attempts to acknowledge the change and suppress a brake application by the reversal of acknowledging Switch ASW, acknowledging relay `S2 will be energized over its previously described pickup circuit and will complete its stick circuit. However, acknowledging relay S3 will not be energized at this time as its pickup circuit is open at the front point of contact c of relay R1. Relay S1 will not be energized at this time since its pickup circuit will be open at front contact b of relay S3, relay S3 remaining deenergized as stated. Therefore, when the engineman returns the acknowledging switch ASW to its normal position the energizing circuit for the winding MV of the magnet valve will, at this time, be open at the front point of contact c of relay Si and the front point of contact a of relay Rt, and an automatic brake application will result after the aforesaid 6 second delay period.

Reset switch RSW is provided to reset the apparatus after the enforcement of an automatic brake application as described in the preceding paragraph. This switch, unlike acknowledging switch ASW, is located on the train at some location not readily accessible to the engineman as, for example, at some point where the engineman will have to leave the engine cab to manipulate the reset switch.

When reset switch RSW is moved to its reverse position, after a change in cab signal indication from clear directly to stop, relay S3 is energized by a circuit extending from terminal B of the battery over the back point of contact n of relay R3, contact b of switch RSW closed in its reverse position, and through the pickup winding of relay S3 to terminal N of the battery. Relay S3 is thus energized completing its stick circuit including its own front contact a. Whether the engineman previously attempted to acknowledge the change from clear to stop makes no difference in the manipulation required by the engineman at this time. lf the engineman did attempt an acknowledgement, relay S2 is energized as previously described and, if he did not so attempt, relay S2 remains deenergized. If relay S2 is deenergized the energizing circuit for the winding MV of the magnet valve is open at the front point of contact a of relay R2. lf relay S2 is energized, the energizing circuit for the winding MV is open at the front point of contact c of relay S1 and the front point of contact a of relay R1. Therefore, in either instance, the usual manipulation of the acknowledging switch is required, subsequent to the manipulation of the reset switch and the resulting pickup of relay S3, in order to energize relay S1 and thus energize the winding MV of the magnet valve. Also contact a of switch RSW, being included in the energizing circuits for relays S2 and Sl, requires that the reset switch RSW be returned to its normal position before the manipulation of acknowledging switch ASW is effective to energize relays S1 and S2. The energization of both relays S1 and S2, by the manipulation of `the reset switch as described, and the reversing and return of the acknowledging switch to its normal position now closes the energizing circuit for winding MV including the front point of contact b of relay S2 and the front point of contact c of relay S1. The train may proceed at the authorized slow speed after the brakes are released.

From the foregoing description it is apparent that, with the arrangement of apparatus of my invention as shown in the drawing, means are provided whereby the change in a cab signal indication from clear directly to stop or slow speed cannot be acknowledged with manipulation of the usual acknowledging switch alone and thereby operate to suppress an automatic brake application, but the change in a cab signal indication from any other proceed indication to stop or slow speed may be acknowledged by proper manipulation of the acknowledging switch and an automatic brake application thereby suppressed.

While I have shown and described only one form of apparatus embodying my invention, it should be understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, whatI claim is:

l. In combination with railway automatic train control apparatus comprising first, second, and third control relays so controlled that the first and third relays only are energized under clear traffic conditions, the first and second relays only are energized under approach medium trahie conditions, the first relay only is energized under approach traffic conditions, and all three relays are deenergized under stop trafiic conditions; and said apparatus also complising a manually operable switch having a first normally closed contact and a second normally open contact, and a normally energized brake valve control magnet having a winding and so constructed that said valve is actuated to cause a brake application only after a predetermined time delay after said winding becomes decnergized; first, second, and third stick relays; a first energizing circuit for said brake valve control magnet winding including said first contact of said switch, a back contact of said second stick relay, a back contact of said third stick relay, and a front contact of said third control relay; a second energizing circuit for said brake valve control magnet winding including said first contact of said switch, said back contact of said second stick relay, a first front contact of said third stick relay, a front contact of said second control relay, and a back contact of said third control relay; a third energizing circuit `for said brake valve control magnet winding including said first contact of said switch, a front contact of said second stick relay, a first back contact of said first stick relay, a front contact of said first control relay, a second back contact of said first stick relay, a first back contact of said second control relay, and said back contact of said third control relay; a fourth energizing circuit for said brake valve control magnet winding including said first contact of said switch, said front contact of said second stick relay, and a front contact of said first stick relay; a pickup circuit for said third stick relay including a second front contact of said first control relay, said second contact of said switch, and said back contact of said third control relay; a pickup circuit for said second stick relay including said second contact of said switch, said back contact of said third control relay, and a second back contact of said second control relay; and a pickup circuit for said first stick relay including a second front Contact of said third stick relay, a first back contact of said first control relay, said second back contact of said second control relay, a second back contact of said first control relay, said second contact of said switch, and said back contact of said third control relay.

2. ln a railway trafiic controlling system comprising train carried automatic train control apparatus including first, second, and third control relays so controlled that the first and third relays only are energized under clear trafiic conditions, the rst and second relays only are energized under approach medium traffic conditions, the rst relay only is energized under vapproach traffic conditions, and all three relays are deenergized under stop traffic conditions; and said apparatus also including a manually operable acknowledging switch having normal and reverse positions and first and second contacts closed in said normal and reverse positions respectively, and a normally energized brake valve control magnet having a control winding and so constructed that said valve is `actuated to cause a brake application only after the expiration of a predetermined period of time after said winding becomes deenergized; in combination; first, second, and third acknowledging relays; a first energizing circuit for said control winding including said first contact of said switch, a back contact of said second acknowledging relay, a back contact of said third acknowledging relay, and a front contact of said third control relay; a second energizing circuit for said control winding including said first contact of said switch, said back contact of said second acknowledging relay, a first front contact of said third acknowledging relay, a front contact of said second control relay; and a back contact of said third control relay, a third energizing circuit for said control winding including said first contact of said switch, `a front contact of said second acknowledging relay, a back contact of said first acknowledging relay, a first front contact of said first control relay, a second back contact of said first acknowledging relay, a back Contact of said second control relay, and said back contact of 4said third control relay; a fourth energizing circuit for said control winding including said first contact of said switch, said front contact of said second acknowledging relay, and a front contact of said first acknowledging relay; a pickup circuit for said second acknowledging relay including said second contact of said switch, said back contact of said third control relay, and a second back contact of said second control relay; a pickup circuit for said third acknowledging relay including said second contact of said switch, said back contact of said third control relay, and a second front contact of said first control relay; and a pickup circuit for said first acknowledging relay including a second front contact of said third acknowledging relay, a back contact of said first control relay, said second back contact of said second control relay, said second Contact Vof? said switch, a second back contact of said first control relay, and said back contact of said third control relay.

3. In a railway traffic controlling system comprising train carried automatic train control apparatus including first, second, and third control relays so controlled that all three relays are deenergized under stop traffic conditions, the first relay only is energized under approach traffic conditions, the first and second relays only are energized under approach medium trafiic conditions, and the first and third relays only are energized under clear traffic conditions; and said apparatus also including a manually operable switch having normal and reverse positions and a first contact closed in its normal position and a second contact closed in its reverse position, and a normally energized brake valve control magnet having a winding and so constructed that the valve is actuated to cause a train brake application only after the expiration of a predetermined period of time after the Winding becomes deenergized; in combination; first, second, and third stick relays; a pickup circuit for said first stick relay including a back contact of said third control relay, said second contact of said switch, a first back contact of said first control relay, a first back contact of said second control relay, a second back contact of said rst control relay, and a first front contact of said third stick relay; a pickup circuit for said second stick relay including said back contact of said third control relay, said second contact of said switch, and said first back contact of said second control relay; a pickup circuit for said third stick relay including said back contact of said third control relay, said second contact of said switch, and a first front contact of said first control relay; a stick circuit for said first stick relay including a second back contact of said second control relay, said back contact of said third control relay and said second back contact of said rst control relay; a stick circuit for said second stick relay including said second back contact of said second control relay and said back contact of said first control relay, a stick circuit `for said third stick relay including said back contact of said third control relay; a first energizing circuit for said magnet winding including a front contact of said third control relay, a back contact of said third stick relay, a back contact of said second stick relay, and said first contact of said switch; a second energizing circuit for said magnet winding including said back contact of said third control relay, a front contact of said second control relay, a second front contact of said third stick relay, said back contact of said second stick relay, and said first contact of said switch; a third energizing circuit for said magnet winding including said back contact of said third control relay, said second back contact of said second control relay, a back contact of said first stick relay, a second front contact of said first control relay, a front contact of said second stick relay, and said first contact of said switch; and a fourth energizing circuit for said magnet winding including a front contact of said first stick relay, said front contact of said second stick relay, and said first contact of said switch.

4. In a railway traffic controlling system comprising train carried cab 'signaling apparatus including first, second, and third control relays so controlled that the first and third relays only are energized under clear traffic conditions, the first and second relays only are energized under approach medium trafiic conditions, the first relay only is energized under approach Itraffic conditions, and all three relay-s are deenergized under stop trafiic conditions; and said apparatus also including a manually operable acknowledging switch having normal and reverse positions and a contact closed only in said reverse position; in combination; first, second, and third stick relays; a pickup circuit for said first stick relay including a front contact of said third stick relay, a first back contact of said first control relay, said switch contact, a first back contact of said second control relay, and a back contact of said third control relay; a pickup circuit -for said second stick relay including said switch contact, said back contact of said third control relay, and said first back contact of said second control relay; a pickup circuit for said third stick relay including said switch contact, a front contact of said first control relay and said back contact of said third control relay; a stick circuit for said first stick relay including a second back contact of said second control relay, said back contact of said third control relay and a second back contact of said first control relay; a stick circuit for said second stick lrelay including said second back contact of said second control relay and said back contact of said third control relay, and a stick circuit for said third stick relay including said back contact of said third control relay.

5. In a railway traffic controlling system comprising train carried cab signaling apparatus including first, second, and third control relays so controlled that the first and third relays only are energized under clear traffic conditions, the first and `second relays only are energized under approach 4medium traffic conditions, the first relay only is energized under -approach trafiic conditions, and all the relays are deenergized under stop traffic conditions; and said apparatus also including a manually operable acknowledging switch having normal and reverse positions and a contact closed only lin said reverse position; in combination, first, second, and third stick relays; a manually operable reset switch having normal `and reverse positions and a contact closed only in said reverse position, a first pickup circuit for said third stick relay including a front contact of said first control relay, said contact of said acknowledging switch, and a back contact of said third control relay; a second pickup circuit for said third stick relay including said contact of said reset switch, and said back contact of said third control relay; a pickup circuit for said second stick relay including said contact of said acknowledging switch, a rst back contact of the second control relay, and said back contact of said third control relay; `a pickup circuit for said `first stick relay including a front contact of said third stick relay, a first back contact of said first control rel-ay, said contact of said acknowledging switch, said back contact of said third control relay, and said first hack contact of the second control relay; a stick circuit for said third stick relay including said back contact of said third control relay, `a stick circuit for said second stick relay ncluding a second back contact of said second control relay and said back contact of said third control relay; and a stick circuit for said first stick relay including a second back contact of said first control relay, said second back contact of said second control relay, and said back contact of said third control relay.

6. In a railway traffic controlling system comprising train carried cab signaling apparatus including first, second, and third control relays so controlled that the first and third relays only Iare energized under clear traffic conditions, the first and second relays only are energized under approach medium traffic conditions, the first relay only is energized under 'approach traffic conditions, and all three relays are deenergized under stop traffic conditions; and also including an acknowledging switch normally occupying a normal position and manually operable to a reverse position; in combination; first, second, and third stick relays, means controlled by said switch and said first `and third control relays for energizings said third stick relay when traffic conditions change from clear or approach medium to more restricting trafiic conditions other than stop and said switch is reversed, means controlled by said third control relay for maintaining said third stick relay energized when once energized and traffic conditions are more restricting than clear; means controlled by said switch and `said second and third control relays for energizing said second stick relay when traffic conditions change from clear to more restricting trafiic conditions other than approach medium, or from approach medium or approach to more restricting ltraffic conditions, and the switch is reversed; means controlled by said second and third control relays for maintaining said second stick relay energized when once energized and trafiic conditions are more restricting than approach medium; means controlled by said switch, all three said control relays, and said third stick relay, for energizing said first stick relay when trafiic conditions change from less restricting trafiic conditions to more restricting than approach, said third stick relay is energized, and said switch is reversed; and means controlled by all three said control relays for maintaining said first stick relay energized when once energized and trafiic conditions are more restricting than approach.

7. In a railway traffic controlling system comprising train carried automatic train control apparatus including, first, second, and third control relays so controlled that the first and third relays only are energized under clear traliic conditions, the first and second relays only are energized under approach medium traflic conditions, the first relay only is energized under approach traffic conditions, and all three relays are deenergized under stop traffic conditions; and said apparatus also including a manually operable acknowledging switch having normal and reverse positions and a first contact closed only in said normal position and a second contact closed only in said reverse position, and a normally energized brake valve control magnet having a control winding and so constructed that the valve is actuated to cause a brake application only after the expiration of a predetermined period of time after said winding becomes deenergized; in combination; a manually operable reset switch having normal and reverse positions and a first contact closed lonly in said normal position and a second contact closed only in said reverse position; first, second, and third stick relays, a first pickup circuit for said third stick relay including a back contact of said third control relay, said first contact of said reset switch, `said second contact of said acknowlledging switch, and a first front contact of said first control relay; a stick circuit for said third stick relay including said back contact of said third control relay, a second pickup circuit for said third stick relay including said second contact of said reset switch and said back contact of said third control relay; a pickup circuit for said second stick relay including said second contact of said `acknowledging switch, said first contact of said reset switch, said back Contact of said third control relay and a first back contact of said second control relay; a stick circuit for said second stick relay including a second back contact of said second control relay and said back contact of said third control relay; a pickup circuit for said first stick relay including a first `back contact of said first control relay, said first back contact of said second control relay, said back contact of said third control relay, a first front contact of said third stick relay, said second contact of said acknowledging switch and said first contact of said reset switch; a stick circuit for said first stick relay including said back contacts of said first and second control relays and a second back contact of said first control relay;

a first energizing circuit for said magnet control winding including a front contact of said third control relay, a back contact of said third stick relay, a back contact of said second stick relay, and said first contact of said acknowledging switch; a second energizing circuit for said control winding including said back contact of said third control relay, a front contact of said second control relay, a second front contact of said third stick relay, said back contact of said second stick relay, and said first contact of said acknowledging switch; a third energizing circuit for said winding including said back contact of said third control relay, said second back contact of said second control relay, a back contact of said first stick relay, a second front contact of said first control relay, a front l5 contact of said second stick relay and said first contact of said acknowledging switch; and a fourth energizing circuit for said winding including a front contact of said first stick relay, said front contact of said second stick relay, and said first contact of said acknowledging switch. 8. In a railway trafiic controlling system comprising train carried automatic train control apparatus including first, second, and third control relays so controlled that the first and third relays only are energized under clear traffic conditions, the first and second relays only are energized under approach medium traflic conditions, the

first relay only is energized under approach trafiic conditions and all three relays are deenergized under stop trafiic conditions; and said apparatus also including an acknowledging switch normally occupying a normal position and manually operable to a reverse position, and a normally energized brake valve control magnet having a control winding and so constructed that said valve is actuated to cause a brake application only after the expiration of a predetermined period of time after said winding becomes deenergized; in combination; first, second, and third acknowledging relays; a reset switch normally occupying a normal position and manually operable to a reverse position; means controlled by said switches and said first and third control relays for energizing said third stick relay when traffic conditions change from clear or approach medium to more restricting trafiic conditions other than stop and the acknowledging switch is reversed and the reset switch is normal, means controlled by said third control relay for maintaining said third stick relay energized when once energized and trafiic conditions are more restricting than clear, means controlled by said reset switch and said third control relay for energizing said third stick relay when trafiic conditions are more restricting than clear and the reset switch is reversed; means controlled by said switches and said second and third control relays for energizing said second stick relay when traic conditions change from clear to more restricting traffic conditions other than approach medium, or from approach medium or approach to more restricting traffic conditions,

and the acknowledging switch is reversed and the reset switch is normal; means controlled by said second and third control relays for maintaining Isaid second stick relay energized when once energized and traffic conditions are more restricting than approach medium; means controlled 6() by said switches, all three said control relays, and said third stick relay, for energizing said first stick relay when trafiic conditions change from less restricting traffic conditions to more restricting than approach, the third stick relay is energized, and the acknowledging switch is reversed and the reset switch is nor-mal; means controlled by all three said control relays for maintaining said first stick relay energized when once energized and trafiic conditions are more restricting than approach; means controlled by said acknowledging switch, said third control relay, and

said second and third stick relays, for energizing said magnet winding when the acknowledging switch is normal, the third control relay is energized, and the second and third stick relays are deenergized; means controlled by said acknowledging switch, said second and third control relays, and said second and third stick relays for energizing said magnet winding when the acknowledging switch is normal, the second and third control relays lare energized and deenergized respectively, and the second and third stick relays are deenergized and energized respectively; means controlled by said acknowledging switch, said first, second, and third control relays, `and said first and second stick relays, for energizing said magnet winding when the acknowledging switch is normal, `the rst control relay is energized, the second and third control relays are deenergized, and the first and second stick relays are de- 10 1,986,679

energized and energized respectively; and means controlled by said acknowledging switch, and said iirst and second stick relays, for energizing said magnet Iwinding when the acknowledging switch is normal, and the first 'and second 5 stick relays are both energized.

References Cited in the file of this patent UNITED STATES PATENTS Howe June 17, 1930 Lewis Jan. l, 1935 

